Chair control



y 1966 H. w. PARROTT 3,250,567

CHAIR CONTROL Filed Feb. 21, 1964 H64 @V dM.

United States Patent Virginia Filed Feb. 21, 1964,5612 No. 346,575 Claims. (Cl. 297304) This is a continuation-in-part of my application Serial No. 196,770, filed May 22, 1962, entitled Chair Control, now Patent No. 3,136,580.

This invention relates to a chair control for tilting a chair back relative to a chair seat, and in particular, to a chair control for also providing slight resiliency of the chair back in a direction transverse to its normal tilting movement.

In many chair constructions, particularly the oflice-type chairs, the chair back is supported to tilt about a horizontal pivot axis relative to the chair seat. Any other movement of the chair back, such as a lateral movement in line with the pivot axis or a twisting movement about a vertically inclined axis, is virtually non-existent since it is resisted by the chair control. For example, in the typical prior art stenographic posture chair, when the chair occupant reaches to the side to open or close a desk drawer, his back must slide along the stationary chair back. This degree of rigidity has been found undesirable since it causes wear of the occupants clothing and of the chair back, and further causes fatigue of the occupant.

Accordingly, an object of this invention is to provide a chair control that not only tilts the chair back relative to the chair seat, but which also permits slight resilient fiexure of the chair back laterally of the usual tilting movement of the chair back.

Another object of this invention is to provide a chair control which is both economical to fabricate and is dur'able in operation.

In order that these and other objects can be more fully appreciated, reference is herein made to the accompanying drawing, wherein:

' FIG. 1 is a side elevational view of a typical posture chair showing therein the subject chair control;

FIG. 2 is a perspective view of the chair control as disclosed in FIG. 1, with the chair seat removed;

FIG. 3 is an elevational view, partly in section as seen from line 3-3 in FIG. 1 of the chair control; and,

FIG. 4 is a perspective view of a bushing used in the subject control.

FIG. 1 shows a typical chair of the oflice type in which the subject chair control has its most common application. The chair 10 includes a base 12 supported on the floor 14. The base 12 adjustably supports a vertical chair post 16, which in turn supports a chair control 18. The chair control 18 supports a chair seat 20 and a chair back 22 relative to one another and to the base 12. In the chair 10 shown, the chair seat 20 is stationary while the chair back 22 pivots about a generally horizontal pivot axis relative to it.

Referring now to the FIGS. 2 and 3 for a more detailed explanation of the chair control 18, it is seen to include a seat support structure 26 and a back support structure 28 pivoted thereto at pivot means 30. The seat support structure includes a cross member 32 connected intermediate its ends to the chair post 16 and connected at its opposite ends to spaced spider arms 34. The chair seat 20 is mounted on the spider arms 34 in the well known manner. The back support structure 28 includes a U-shaped channel 36, a hinge 38 secured adjustably to the channel 36, and an arm 40 secured adjustably to the hinge 38 and supporting the chair back 22. The pivot means 30 includes a pair of spaced cars 42 formed from the cross member 32 for supporting therebetween the channel 36 of the back support structure 28. A torque rod 44 extends through appropriately mounted bushings 46 (FIG. 4) supported within the cars 42 and channel 36, and forms the pivot axis about which the chair back 22 tilts. The torque rod 44 is keyed atits opposite ends to the spider arms 34 of the seat support structure 26 and intermediate its ends through the interaction of torque lever 48 to the channel 36 of the back support structure 28. Upon a clockwise displacement of the back support structure 28 (as seen in FIG. 1 or 2) the torque rod 44 is strained from its opposite ends towards its center to create a resilient counterclockwise returning force.

The control 18 as described herein is identical in all respectsto that disclosed in myabove-mentioned Patent No. 3,136,580. The above-identified application, how ever, is directed specifically to a particular arrangement of securing the torque rod 44 (as herein numbered) t0 the back and seat support members to provide the desired resilient spring back for the tilted chair back.

It has been found that the subject chair control 18 otters a unique action that adds to the comfort of the chair occupant. This action includes a slight fiexure of the chair back 22 laterally of the normal tilting action of the chair back, as shown generally by the arrows 50 in FIG. 3. This sideways fiexure is beneficial since it gives the chair occupant a new sense of freedom and comfort, such as permitting him to reach sideways without sliding along the chair back. Several structural details of the disclosed control permit the slight lateral resiliency of the chair back, the effect that each singularly has on the total action varying with the size and type of the particular control.

For example, the opposite side walls 52 of the U-shaped channel 36 are connected at the pivot means 30 to the seat support structure 26, and as such are held at the torque rod substantially fixed transversely of the pivot axis. However, the channel spaced axially from the pivot means is generally free to move transversely, and

in fact is quite resilient to torsional deflection about its axial center axis. Note that a lateral force applied to the chair back 22 twists the channel 36 about its axial center axis, and this torsional force is resisted at the pivot axis by the pivot means 30. The pivot means 30 consists of four bushings 46 (FIGS. 3 and 4) held separately at 56 to the ear 42 or channel 36 and held together back to back by flange 58 and square torque rod 44 received within the aligned cylindrical openings 60. When the pivot means is subjected to a torsional force, the bushings on the seat support structure can be and are moved slightly relative to the bushings on the back support structure. This is caused because the torsional force of the channel 36 wedges the ears 42 apart slightly at their free ends, and the bushings are held together only by a single torque rod. Additionally the pointed contacts of the square torque rod on the periphery of cylindrical opening 60 permit a slight further movement relative to one another, particularly, as herein, where the bushings are of a durable plastic type material and are slightly flexible themselves. Furthermore, the small axial distance between the spaced pivot means (between the ears 42) as compared to the cantilevered distance between the chair back 22 and the pivot means magnifies the transverse defiections of the chair back as compared to any transverse movements of the pivot means 30. It has been observed that a transverse movement of the chair back from both sides of the vertical can be as high as 10 to '15 degrees with only little observable movement taking place at the pivot means.

While only a single embodiment of the subject control has been disclosed, it will be obvious to those skilled in the art, that other modifications can be made therein without departing from the inventive concept disclosed herein. Accordingly, it is desired that the invention be limited only by the claims hereinafter following.

What is claimed is:

1. For use in a chair control for tilting a chair back relative to a chair seat, and including seat support structure for supporting the chair seat, back support structure for supporting the chair back, and pivot structure for pivoting the back support structure and seat support structure relative to one another about a generally horizontal pivot axis, the improvement comprising the combination of the back support structure being in part U-shaped in transverse cross-section as defined by a plane parallel to the pivot axis, and having spaced sidewalls joined at corresponding ends by a common interconnecting wall, said pviot structure including a rod fixedly connected separately to each of the sidewalls at a location spaced from the interconnecting wall, said pivot structure including mounting ears on the seat support structure spaced apart in the direction in line with the pivot axis a distance substantially less than the distance between the chair back and the pivot axis and straddling the U-shaped section of the back support structure, said pivotstructure further including multiple piece bearings each formed by at least two elements fixed, respectively, snugly to the back and seat support structures while being generally independent of one another, and being maintained in proper operational position relative to one another by said rod received snugly in aligned through openings of the elements, said rod having a cross-section of similar dimension to the through openings of the bearing elements and of different shape such as of a square contour as compared to a cylindrical through opening, each of the ears being cantilevered from the seat support structure and having a connection at its free end to the pivot structure at the pivot axis so as to permit a slight fiexure of the free ends of the ears upon the lateral displacement of the chair back relative to the pivot axis, whereby the chair back has a limited degree of resiliency or available flexure in a direction transverse to the usual pivoting of the chair back.

2. A combination for use in a chair comprising a seat support having side walls interconnected by a cross member, a pair of spaced ears carried by said cross member perpendicular to said cross member and having aligned apertures, a back support for carrying a chair back and having a pair of spaced legs with an aligned opening in each leg of said back support aligned with said aligned apertures, a respective bearing member for each aperture and opening with the bearing members in said openings pivotally supporting said back support, a flange on one side of each bearing with the flanges on each bearing located between the adjacent respective ear and adjacent respective leg for restraining movement of said bearing members along the axis of said bar, and a torsion bar held by opposite side walls of said seat support structure against rotation and passing through said bearing members to locate the axis of rotation of said back support along the axis of said bar.

.3. A-combination for use in a chair having means for torsionally stressing a torsion bar on pivoting of a chair back relative a chair seat, the improvement comprising a seat support having side walls interconnected by a cross member for carrying said seat with said side walls holding said bar against rotation, a pair of spaced ears carried by said cross member perpendicular to said cross member and having aligned apertures, a back support for carrying said chair back and having a pair of spaced legs with an aligned opening in each leg for alignment with said aligned apertures, a respective bearing member for each aperture and opening with the bearing members in said openings pivotally supporting said back support, and a flange on one side of each bearing with the flanges on each bearing located between the adjacent respective ear and adjacent respective leg for restraining movement of said bearing along the axis of said bar with each bearing member encircling said torsion bar for rotation relative thereto.

4. For use in a chair of the type wherein a back support is arranged to torsionally stress a torsion bar in response to pivoting movement of said back support relative a seat support having opposite side walls holding said torsion bar against rotation with said side walls interconnected by a cross member having a pair of spaced ears perpendicular to the plane of said cross member and wherein aligned apertures are provided in said ears aligned with an opening in said back support, the improvement comprising a respective bearing member for said apertures and opening with each bearing member encircling said torsion bar and the bearing member in said opening pivotally supporting said back support relative to the axis of said torsion bar, and a flange at one end of said bearing members in said apertures with said flange located between the adjacent respective ear and said back support for restraining movement of said bearings along the axis of said bar;

5. For use in a chair of the type wherein a back support is arranged to torsionally stress a torsion bar in response to pivoting movement of said back support relative a seat support having opposite side walls holding said torsion ba: against rotation with said side walls interconnected by. .a cross member having a pair of spaced ears perpendicular to the plane of said cross member and wherein aligned apertures are provided in said ears aligned with an opening in said back support, the improvement comprisinga respective bearing member in each aperture encircling'satid bar for supporting said torsion bar intermediate the erius of said bar, a bearing member in said back support opening and encircling said torsion bar for pivotally supporting said back support relative to the axis of said torsion bar, and a flange at one end of each bearing member in said apertures with said flanges located between the adjacent respective ear and said back support for restraining movement of said bearings along the axis of said bar.

References Cited by the Examiner UNITED STATES PATENTS 2,757,051 7/1956 Wilmer et a1 312-641 X 2,778,409 1/ 1957 Soderberg 297-304 3,027,191 3/1962 Lie 297-306 FRANK B. SHERRY, Primary Examiner.

J. S. PETRIE, G. O. FINCH, Assistant Examiners. 

4. FOR USE IN A CHAIR OF THE TYPE WHEREIN A BACK SUPPORT IS ARRANGED TO TORSIONALLY STRESS A TORSION BAR IN RESPONSE TO PIVOTING MOVEMENT OF SAID BACK SUPPORT RELATIVE A SEAT SUPPORT HAVING OPPOSITE SIDE WALLS HOLDING SAID TORSION BAR AGAINST ROTATION WITH SAID SIDE WALLS INTERCONNECTED BY A CROSS MEMBER HAVING A PAIR OF SPACED EARS PERPENDICULAR TO THE PLANE OF SAID CROSS MEMBER AND WHEREIN ALIGNED APERTURES ARE PROVIDED IN SAID EARS ALIGNED WITH AN OPENING IN SAID BACK SUPPORT, THE IMPROVEMENT COMPRISING A RESPECTIVE BEARING MEMBER OF SAID APERTURES AND OPENING WITH EACH BEARING MEMBER ENCIRCLING SAID TORSION BAR AND THE BEARING MEMBER IN SAID OPENING PIVOTALLY SUPPORTING SAID BACK SUPPORT RELATIVE TO THE AXIS OF SAID TORSION BAR, AND A FLANGE AT ONE END OF SAID BEARING MEMBERS IN SAID APERTURES WITH SAID FLANGE LOCATED BETWEEN THE ADJACENT RESPECTIVE EAR OF SAID BACK SUPPORT FOR RESTRAININ MOVEMENT OF AIS BEARING ALONG THE AXIS OF SAID BAR. 